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T. L. TALIAFERRO.

PROCESS OF LACQUERINGVSHEET METAL.

APPLlCATlON FILED DEC-30.1918. 1,312,815.

Patented Apg. 12, 1919 UNITED STATES mom-1. 1am: I

PATENT OFFICE.

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Sp n of Letters intent. Patented Aug. 12, 1919.

Application filed December so, 1918. Serial no. 288,980.

To all whom it may.

' .Be it known that I, -Tiimms Lnomn TALIArnnRo, a citizen of the UnitedStates, residing at Chicago, in the county of Cook, State of Illinois, have invented certain new and useful Improvements in Processes of Lacquering Sheet Metal, of which'the following is a description, reference being had to the accompanying drawing and to the figures of reference marked thereon.

The invention relates to a new and useful improvement in the process of lacquering sheet metal, and more .particularly to a process which contemplates the lacquering of .both sides of a sheet of metal or the applying of two coats of lacquer to one or both sides of a sheet of metal.

Prior to my invention it has been a common expedient to coat sheet metal with an acid resistlng lacquer made from a combina- V tion of oils and gums which when subjected to a baking temperature forms a comparatively hard acid resisting surface. It has been the usual practice to lacquer one side of a sheet of metal and then subject the same to abaking temperature until the particles of the lacquer become fused or amalgamated, after which the other side of the sheet of metal is lacquered and the sheet again subjected to a baking temperature. -In the carrying out of this process considerable time is required as the sheet of metal must be subjected to the baking temperature for an'interval of time necessary to bring about the twice baking of the sheet. On the other hand, the side of the sheet which is first coated is twice subjected to a baking temperature and this often results in a discoloring of the lacquer.

An object of the present invention is to provide a process of lacquering sheet metal, wherein both sides of the sheet may bebaked simultaneously, thus avoidmg the'ob ection to the twice baking of one of the lacquered perature for a short interval of time in order to bring about a setting of the lacquer. During this drying interval which is very short,

volatile matter particularly near the sur- -sufficient to with lacquer, after which the entire sheet is subjected to a baking temperature for an interval of time to bring about a thorough fusing or amalgamating of the particles of the lacquer. This process may also be applied to the double coating of one face of a sheet of metal. The first coating is applied and dried sufficiently to form a film on the coating of lacquer to permit a second coating to be placed on the first film covered surface, after whlch the sheet is baked. In the double coating of a sheet of metal as at present practised, the first coating is bakedrmgmg about a fusing of the particles of lacquer, after which the appl1ed and baked. This first coating of lacquer 1s subjected to the twice baking, and, furthermore, inasmuch as the first coating has been baked there is little or no chance of the particles of'lacquer in the second coat- 1ng becoming fused or amalgamated with the partlcles in the first coating. By my process, however, wherein the first coating is merely dried sufliciently to permit the second coat1ng to be applied thereon, when the bak ng takes place both the layers of lacquer Wlll become thoroughly fused together and amalgamated, thus forming a very durable coating for the sheet of metal.

It s believed the roce'ss, as I prefer to practlserthe same, W1 1 be more clearly understood by reference to the accompanying 1ng oven and two coating stations, each of which is adapted to apply a coating to a sheet of metal, and a conveying system for conveying the sheet first to one coating device, then to the drying oven, then to-the second coating device and finally to the bakmgoven.

' The drying oven is indicated at D, and consists of an elongated casing, having side and end Walls, in which is provided suitable burnersl-l, for heating a circulating air passing through the drying oven. The baksecond coating is ing oven is indicated at B and consists also of an elongated casing provided with suitable burners 2-2, by which the circulating air may be heated and the oven brought up to a baking temperature.

The sheets which are to be lacquered are first passed-through the coating station P, which consists of two rotating coating rolls 3 and 4, and a short endless carrier 5, which receives the sheets as they pass through the rolls and presents the same to the endless carrier 6 which is adapted to carry the sheets through the drying oven B. This endless carrier is provided with a series of arms 77, between which the sheets are placed, while said arms are substantially horizontally disposed, after which the arms pass to vertical position and then convey the sheets standing on edge through the drying oven B. The drying oven is preferably heated to a temperature of approximately 250 and the length of the oven and the timing of the movement of the endless carrier 6 is such that the sheet is in this drying oven for approximately five minutes. This subjecting of the lacquered sheet to a drying temperature for the short interval of ap roximately five minutes causes the volati e parts of the lacquer, particularly near the surface thereof, to be driven oil and more orless of an oxidizing effect to take place to form a film on the surface of the coating of the lacquer. This film is sufiiciently hard to protect the lacquered surface so that the sheet may be readily handled for bringing about the coating of the other side of the sheet. The sheets after leaving the oven B are deposited in horizontal position on an endless carrier 8, which directs the sheets to the second printing station, indicated at P. This coating station consists of coating rolls 9 and 10. The other side of the sheet is coated at this station and the sheet is delivered on to the endless carrier 11. Associated with the baking oven B is an endless carrier 12, having arms 13 which are adapted to convey the lacquered sheets in a manner similar to the endless carrier 6, position the sheets in vertical arrangement and carry the sheets through the baking oven B. This baking oven is preferably heated to a temperature of approximately 325 and is of such a length as to require approximately fifteen minutes for the sheet to pass through the same.

It will be understood, of course, that the tem erature of both the drying oven and baklng oven may be greatly var ed without departing from the spirit of the invention and the figures given are for the purpose of giving a specific description of one method of carrying out my improved process. It will also be understood that the time required for the sheet to pass through both the drying oven and the baking oven may be greatly varied without departing from the spirit of the invention, for similar reasons.

Asthe sheet passes through this baking oven B, it is sub ected to a baking temperature and for an interval of time which causes the particles of the lacquer to become fused or amalgamated, thus forming from the lacquered coating a hard acid resisting surface which Will.protect the surface of the metal.

- If two coats of lacquer are to be applied to the same side of a sheet, the only difference in the apparatus is an arrangement of the conveyor so that, after the first side of the sheet has been coated, as it passes to the coating device the same side will again be coated. In other words, the drying of the first coating of lacquer to enable the sheet to be handled for the coating on the opposite side of the sheet is also sufficient to enable a second coating of lacquer to be ap-.

plied to the same side of the sheet.

From the above, it will be apparent that the essential features of my improved process consists inthe subjecting of the coated lacquered sheet to a drying temperature a su clent time interval to form a protecting film on the coating of lacquer which has been applied to the sheet, so as to enable said sheet to be readily handled and a second coating applied thereto, after which both coatings, whether on the opposite side or on the same side of the sheet, are subjected to a baking temperature for a time interval to permit the thorough fusing or amalgamating of all the particles of lacquer, thus forming a hard acid resisting surface. It Wlll also be obvious that I have substituted f 0r the first baking step, as heretofore practlsed, in the coating of a lacquered sheet, a drying step which is-of a very short interval of tlme and this greatly reduces the complete time interval required for the lacquering and baking of both sides of the sheet. Then, again, I have provided a process in which the sheets are lacquered and baked on both sides with a minimum amount of handling of ,the sheet. Heretofore where the sheets have been lacquered and baked on one side, they have usually been stacked and finally taken to a second oven and printing sheets. This is a great advantage as it is always desirable to avoid the handling of the1 baked lacquered sheets as much as possib e.

It is obvious that the specific embodiment of my improved process may be greatly varied without departing from the spirit of the invention which is set forth in the appended claims. 4

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. The process of lacquering sheet metal including coating the sheet of metal with lacquer, subjecting the coated sheet to a drying atmosphere for a sufficient period only to cause a protecting film to form on the lacquer coating, again coating the sheet with lacquer and subjecting the twice coated sheet to a baking atmosphere for an interval of time suflicient to cause a thorough fusing or amalgamating of the particles of the lacquer.

2. The process of lacquering sheet metal including coating the sheet of metal with lacquer, subjecting the coated sheet to a drying atmosphere of approximately 250 for an interval of time of approximately five minutes or until some of the volatile matter is driven off and by oxidization a protecting film is formed on the coating of lacquer, then subjecting the coated sheet to a second coating of lacquer and subjecting the same to a baking temperature of approximately 325 for approximately a time interval of fifteen minutes or until the particles of the laquer are thoroughly fused or amalgamated together, thus forming a hard acid resisting surface.

3. A process of lacquering sheet metal including passing the sheet through a coating apparatus wherein one surface of the sheet is coated with lacquer, then passing the sheet through a drying oven at a sufficient temperature and for an interval of time to bring about the formation of a protecting film on the coating of lacquer, then passing the sheet directly through a second coating apparatus wherein a second coating of lacquer is applied thereto and finally passing the sheet through a baking oven at a sufficient temperature and for an interval of time to bring about a thorough fusing or amalgamating of the particles of the lacquer in both coatings which have been applied thereto.

4. The process of lacquering both sides of a sheet of metal, which consists in passing the sheet through a coating apparatus and coating one surface of the sheet with lacquer, then passing the coated sheet through a drying oven at a suflicient temperature and for an interval of time to'cause the coating of lacquer to set, then passing the lacquered sheet through a second coating apparatus and coating the opposite face thereof with lacquer, and then passing the sheet through a baking oven at a temperature and for an interval of time for causing the particles of lacquer to become fused or amalgamated.

5. The process of lacquering sheets of metal which consists is passing the sheets one after another in succession through coating rolls, wherein one surface of each sheet is coated with lacquer, placing the'coated sheets in vertical position one behind the other, and passing the same through a drying oven at a temperature sufficient to cause the coating of lacquer to set, then passing the sheets in succession one after another directly from the drying oven through a coating apparatus, wherein the sheet is again coated with lacquer, and finally arranging the sheets in vertical position one behind the other and passing the same through a baking oven at a suflicient temperature and for an interval of time to bring about the thorough fusing or amalgamating of the particles .of lacquer.

In testimony whereof I aflix my signature.

THOMAS LUOIEN TALIAFERRO. 

